The present invention relates to the field of environmental science and technology focusing on decreasing or preventing sub-surface geological matter (e.g., ground or earth, or/and water) contamination by agrochemicals. More particularly, the present invention relates to a method of exposing an agricultural substrate (plant matter, animal matter) to an agrochemical, and to a method of decreasing or preventing sub-surface geological matter contamination resulting from exposing an agricultural substrate to an agrochemical. The present invention further relates to a composition used in those methods, and to an article-of-manufacture including the composition.
Agricultural Substrates:
Herein, with respect to the field and art of the present invention, an ‘agricultural substrate’ is to be understood as generally being any plant matter or animal matter that is cultivated, bred, raised, grown, developed, maintained, or/and stored, as part of an agricultural process or agricultural type of process. In a non-limiting manner, an agricultural substrate is also to be understood as generally being any plant matter or animal matter that is cultivated, bred, raised, grown, developed, maintained, or/and stored, as part of a process involving or/and relating to, agronomy (i.e., scientific agriculture), horticulture (i.e., art and science of growing flowers, fruits, vegetables, and shrubs, especially in gardens or orchards), botany (i.e., art and science of plants), zoology, marine biology, among other fields, which are either known, or may be considered, as being related or connected to the field of agriculture.
Plant matter is to be understood as generally being any number and type of plant entity, structure, substance, or material, which is in some stage of being cultivated, bred, raised, grown, developed, maintained, or/and stored, as well as to any number and type of plant entity, structure, substance, or material, which may be, or has been, harvested or cut. Harvested or cut plant matter is to be understood as generally being plant matter which has been entirely or wholly separated, detached, or removed, from the soil or earth hosting the plant matter. Such separating, detaching, or removing, of the plant matter is performed by pulling or/and cutting the plant matter out of, or out from, the soil or earth hosting the plant matter, at the point or location of cultivating, breeding, raising, growing, or developing, of the plant matter, such that the harvested plant matter is no longer considered plant matter that is actively cultivated, bred, raised, grown, or developed. In a non-limiting manner, exemplary types of plant matter which are particularly relevant to the field and art of the present invention are crops, plants, trees, bushes, shrubs, vines, flowers, and weeds. Exemplary types of plant matter which are especially relevant to the field and art of the present invention are commercial grain, vegetable, or fruit, types of crops or plants, and, flowers.
Animal matter is to be understood as generally being any number and type of animal entity, structure, substance, or material, which is living and in some stage of being bred, raised, grown, developed, maintained, or/and stored, as well as to any number and type of animal entity, structure, substance, or material, which may become, or is, non-living as a result of being slaughtered (typically, as a source of human consumable meat, poultry, or fish). In a non-limiting manner, exemplary types of animal matter which are particularly relevant to the field and art of the present invention are livestock, farm animals, zoo animals, marine animals, and sheltered animals. Exemplary types of animal matter which are especially relevant to the field and art of the present invention are commercial livestock, farm animals, and marine animals, such as cattle (cows), sheep (lamb), hogs (pigs), goats, oxen (steer), horses, chickens, turkeys, and fish.
Agrochemicals:
Herein, with respect to the field and art of the present invention, an ‘agrochemical’ is to be understood as generally being any chemical, biological, or/and physical, entity, structure, substance, material, compound, composition, formulation, or organism, singly or in combination, which is applied or dispensed to, or/and upon, the outer (air or atmosphere exposed) surface of an agricultural substrate (as defined hereinabove) or/and immediately surrounding environment of an agricultural substrate, as part of cultivating, breeding, raising, growing, developing, maintaining, or/and storing, the agricultural substrate.
A first main category of agrochemicals particularly relevant to the field and art of the present invention includes agrochemicals that promote or/and enhance cultivating, breeding, raising, growing, developing, maintaining, or/and storing, of agricultural substrates, in a positive manner (i.e., with respect to the agricultural substrates). Exemplary sub-categories of agrochemicals included in this first main category of agrochemicals are fertilizers, growth stimulators, plant growth regulators (those which ‘positively’ promote or/and enhance plant growth and development), hormones, synergists, and similar types of agrochemicals, which are applied or dispensed to, or/and upon, the outer surface or/and immediately surrounding environment of plant matter types of an agricultural substrate, as part of cultivating, breeding, raising, growing, developing, maintaining, or/and storing, the plant matter, in a positive manner (i.e., with respect to the plant matter).
A second main category of agrochemicals particularly relevant to the field and art of the present invention includes agrochemicals that promote or/and enhance cultivating, breeding, raising, growing, developing, maintaining, or/and storing, of agricultural substrates, in a negative or inhibitory manner (i.e., against ‘enemies’ of the agricultural substrates). An important exemplary sub-category of agrochemicals in this second main category of agrochemicals is pesticides, which are applied or dispensed to, or/and upon, the outer surface or/and immediately surrounding environment of plant matter or animal matter types of an agricultural substrate, as part of cultivating, breeding, raising, growing, developing, or maintaining, the plant matter or animal matter, in a negative or inhibitory manner (i.e., against enemy ‘pests’ of the plant matter or animal matter).
A pesticide, as an important exemplary sub-category of agrochemicals, is commonly known as generally being any chemical that is used to kill pests, such as insects, and rodents. Herein, in a more encompassing and general manner, which is particularly relevant to the field and art of the present invention, a pest may be considered as essentially any living plant or animal organism, or any microorganism, which interferes with or/and inhibits cultivating, breeding, raising, growing, developing, maintaining, or/and storing, of agricultural substrates (plant matter, animal matter). Pesticides may be divided and classified into major groups [1]. Major pesticide groups are: acaricides or miticides (lethal to ticks and mites), algicides, antifeedants, avicides (lethal to birds), bactericides, bird repellants, chemosterilants, fungicides, herbicide safeners, herbicides, insect attractants, insect repellants, insecticides, mammal repellants, mating disrupters, molluscicides, nematicides, plant activators (activate plant defense mechanisms against pests), plant growth regulators (those which inhibit pest plant growth), rodenticides, synergists, and virucides. This classified list of major pesticides groups represents at least fourteen hundred pesticide compounds. Moreover, each major pesticide group is sub-divided into chemical or other classes.
Geological Matter and Sub-Surface Geological Matter:
Herein, with respect to the field and art of the present invention, ‘geological matter’ is to be understood as generally being a type of ground or earth, or/and water. A given geological matter can be generally characterized as being inorganic, organic, non-aqueous, aqueous, or any combination thereof. In general, there exist various different forms of a ground or earth type of geological matter, and various different forms of a water type of geological matter.
Exemplary specific forms of a ground or earth type of geological matter which are particularly relevant to the field and art of the present invention are soil, sand, rocks, stones, pebbles (i.e., small rocks or stones), sediment (i.e., matter deposited by water or wind), fragments thereof, or any combination thereof (e.g., gravel, being an unconsolidated combination (mixture) of rock fragments or pebbles).
Exemplary specific forms of a water type of geological matter which are particularly relevant to the field and art of the present invention are water that is, or/and may be, present or contained in, typically naturally existing, but possibly human made, rivers, streams, lakes, ponds, pools, water reservoirs, wells or springs (i.e., flows of water from the ground or earth), ground water, and aquifers. Additional exemplary specific forms of water which are also relevant to the field and art of the present invention are water that is, or/and may be, present or contained in human made (commercial size) large volume water receiver, collection, or/and storage, vessels, containers, reservoirs, or chambers.
‘Sub-surface geological matter’ is to be understood as generally being any geological matter, as just defined, but limited to only that entire, or to only that part of, geological matter which is located below or beneath the top or uppermost surface layer of a form of ground or earth, or of a form of water. Accordingly, sub-surface geological matter is a particular or special case of the more general geological matter.
For example, within an agricultural or agricultural type of field or plot of land, plant matter and animal matter types of agricultural substrates are physically located and function (i.e., they exist by breathing, eating, etc.) upon the air or atmosphere exposed surface of the top or uppermost surface layer of ground or earth. In contrast to animal matter, plant matter, in particular, due to the presence of a depth dependent ‘living’ plant root system and associated plant roots, is also partly physically located and functions (exists) within and throughout such a top or uppermost surface layer. Accordingly, such a top or uppermost surface layer is ordinarily characterized by including within and throughout it a living plant root system and associated plant roots, and can therefore be classified, and equivalently referred to, as a plant matter root layer.
All geological matter which is located below or beneath the top or uppermost surface layer (i.e., the plant matter root layer) of ground or earth is collectively considered as sub-surface geological matter. Thus, geological matter which is contained upon the air or atmosphere exposed surface of the top or uppermost surface layer (i.e., the plant matter root layer) of ground or earth, as well as geological matter which is contained within and throughout the top or uppermost surface layer (i.e., the plant matter root layer) of ground or earth, are not considered as sub-surface geological matter.
The depth of the top or uppermost surface layer (i.e., the plant matter root layer) of ground or earth which extends from immediately below or beneath the air or atmosphere exposed surface to immediately above what is considered sub-surface geological matter, clearly varies, and primarily depends upon the type or kind, and, properties, characteristics, and behavior, of plant matter, in particular, regarding the living plant root system and associated plant roots which are located and function (exist) within and throughout the top or uppermost surface layer (i.e., the plant matter root layer). This depth also depends upon the type or kind, and, properties, characteristics, and behavior, of geological matter which is contained upon the air or atmosphere exposed surface, and upon the type or kind, and, properties, characteristics, and behavior, of geological matter which is contained within and throughout the top or uppermost surface layer (i.e., the plant matter root layer) of ground or earth.
Typically, this depth from immediately below or beneath the air or atmosphere exposed surface to immediately above what is considered sub-surface geological matter, extends in a range of between about 5 centimeters and about 1.5 meters. Clearly, this depth proportionately increases for proportionately larger plant matter types of agricultural substrates which have correspondingly proportionately larger and deeper living plant root systems and associated plant roots located and functioning (existing) within and throughout the top or uppermost surface layer (i.e., the plant matter root layer) of ground or earth. It is noted that within and throughout this depth, although below or beneath the air or atmosphere exposed surface of ground or earth which hosts plant matter and animal matter types of agricultural substrates, that agrochemicals also function as part of cultivating, breeding, raising, growing, developing, maintaining, or/and storing, the agricultural substrates, especially with respect to the plant matter root layer of plant matter.
As previously stated hereinabove, all geological matter which is located below or beneath the top or uppermost surface layer of a form of ground or earth, or of a form of water, is considered as sub-surface geological matter. Exemplary specific forms of a ground or earth type of sub-surface geological matter are soil, sand, rocks, stones, pebbles (i.e., small rocks or stones), sediment (i.e., matter deposited by water or wind), fragments thereof, or any combination thereof (e.g., gravel, being an unconsolidated combination (mixture) of rock fragments or pebbles). Exemplary specific forms of a water type of sub-surface geological matter are water that is, or/and may be, present or contained in, typically naturally existing, but possibly human made, ‘sub-surface’ rivers, streams, lakes, ponds, pools, and water reservoirs. Additional exemplary specific forms of such water type of geological matter are water that is, or/and may be, present or contained in human made (commercial size) ‘sub-surface’ large volume water receiver, collection, or/and storage, vessels, containers, reservoirs, or chambers.
Ground water (i.e., water found underground beneath the earth's surface within partially or fully saturated soil or/and permeable (e.g., porous) rock), and water of an aquifer (i.e., a water-bearing rock or rock formation, or an underground layer of permeable (porous) rock, sand, etc., containing water), are special cases of sub-surface geological matter, wherein, for each of these forms of water, all of the water is ‘entirely’ located below or beneath the top or uppermost surface layer of a form of ground or earth.
As indicated hereinabove, sub-surface geological matter begins at, or from, a depth in a range of between about 5 centimeters and about 1.5 meters below or beneath the air or atmosphere exposed surface of the top or uppermost surface layer of ground or earth, or of water. Moreover, sub-surface geological matter can extend until a depth of several hundreds of meters, and even to a depth of more than 1000 meters, below or beneath the air or atmosphere exposed surface of the top or uppermost surface layer of ground or earth, or of water.
Herein, the term ‘geological matter’ is to be understood as defined hereinabove, and thus, in a general manner, may include reference to sub-surface geological matter, unless otherwise specifically stated herein. However, the term ‘sub-surface geological matter’ is to be understood only as specifically just defined, that is, as a particular or special case of geological matter.
On-Going Problems Caused by Sub-Surface Geological Matter Contamination Resulting from Exposing Agricultural Substrates to Agrochemicals:
In agricultural or agricultural types of processes which involve applying or dispensing agrochemicals to, or/and upon, outer surfaces or/and immediately surrounding environments of plant matter or/and animal matter types of agricultural substrates, as part of cultivating, breeding, raising, growing, developing, maintaining, or/and storing, the agricultural substrates, the resulting distribution (pervasiveness), transport (mobility), and fate (i.e., as relating to persistence, degradation, transformation, or/and conversion), of the agrochemicals into the above stated types and forms of sub-surface geological matter has led to extensive contamination or pollution of the sub-surface geological matter.
Distribution, transport, fate, ecological risk, and health effects, of agrochemicals, and possible degradation, transformation, or/and conversion products thereof, in sub-surface geological matter, particularly, in the above stated water or aqueous forms of sub-surface geological matter, which are, or/and come in direct contact with, or/and lead to, sources of drinking water, are of great concern because of proven or potentially hazardous (poisonous or toxic) properties and characteristics of the resulting sub-surface geological matter contamination or pollution.
Largely based on the fact that ground water accounts for more than about 95% of the earth's usable fresh water resources, ground water contamination or pollution is a critical issue, and intensive efforts are continuously being invested in the development of improved and new technologies for treating or remediating sub-surface geological matter contaminated or polluted with agrochemicals.
Among the wide variety of different types of sub-surface geological matter contaminants or pollutants, agrochemicals, particularly those composed of, or which include, halogenated (especially, chlorinated) organic compounds, are arguably the most common, pervasive (widespread), persistent (e.g., having half-lives ranging from days to 10,000 years), proven or potentially hazardous (poisonous or toxic), undesirable contaminants or pollutants in the above stated types and various forms of sub-surface geological matter. Many such types and forms of sub-surface geological matter are, or/and come in direct contact with, or/and lead to, sources of drinking water. Currently, numerous halogenated (especially, chlorinated) organic compound types of agrochemicals are still applied in large quantities on large scales, in commercial agricultural and industrial processes, by exploiting their high performance, in addition to their relatively high stability and resistance to chemical and biological degradation. It is now recognized that these properties, which are essential to commercial agriculture and industry, have devastating effects on sub-surface geological matter environments, translating to undesirable short and long term human health problems.
Among the wide variety of different halogenated (especially, chlorinated) organic compound agrochemicals used in agricultural or agricultural types of processes which involve applying or dispensing to, or/and upon, outer surfaces or/and immediately surrounding environments of plant matter or/and animal matter types of agricultural substrates, as part of cultivating, breeding, raising, growing, developing, maintaining, or/and storing, the agricultural substrates, halogenated organic compound members in the above listed major pesticide groups are the most widely used. Within the major pesticide group of herbicides, three particularly well known halogenated organic herbicide sub-groups or classes are: the chlorotriazine herbicide sub-group or class, the chloroacetanilide herbicide sub-group or class, and the halogenated aliphatic herbicide sub-group or class. The well known chlorinated organonitrogen herbicides (CONHs) encompass all halogenated organic herbicide members (especially triazines, such as atrazine and cyanazine) in the chlorotriazine herbicide sub-group, and all halogenated organic herbicide members (such as alachlor and metolachlor) in the chloroacetanilide herbicide sub-group.
The popularity of using triazine halogenated organic herbicide type pesticides in commercial agriculture is based on their herbicidal effectiveness, commercial affordability, and lack of comparable commercial alternatives. Halogenated organic herbicide type pesticides, in general, and CONHs, in particular, are commonly used for pre- and post-emergence weed control during the growing of various crops, for example, corn, soybean, and sugarcane, and have become an integral component of modern commercial agriculture worldwide. The U.S. Environmental Protection Agency (EPA) estimates that 36 and 16 million kilograms of atrazine and cyanazine, respectively, are dispersed among farms and croplands annually across the nation [2]; application of alachlor tends to be similar to atrazine [3-5].
Halogenated organic herbicide type pesticides, in general, and CONHs, in particular, and many of their degradation products, are non-volatile particulate substances (nearly all) or liquids (some) which, at typical contaminant concentrations (e.g., ppb-ppm range) are soluble in water, and are mobile within and throughout permeable (porous) sub-surface geological matter (soil, sand, rocks, stones, pebbles, sediment, gravel), and of course, water. Many halogenated organic herbicide type pesticides, for example, the CONHs—atrazine, cyanazine, simazine, alachlor, and metolachlor, and their degradation products (especially higher water mobile halogen (typically, chlorine) containing derivatives), are pervasive, persistent, proven or potentially hazardous (poisonous or toxic), undesirable contaminants or pollutants of sub-surface geological matter, particularly, in the above stated water or aqueous forms of sub-surface geological matter, which are, or/and come in direct contact with, or/and lead to, sources of drinking water.
Halogenated organic herbicide type pesticides, in general, and CONHs, in particular, among other types of agrochemicals, have been measured in drinking water sources at concentrations exceeding their EPA promulgated maximum contaminant levels (MCLs) [3, 5, 6]. The possibility of widespread sub-surface geological matter contamination or pollution, and consequent deterioration of water quality, resulting from exposing agricultural substrates to agrochemicals, such as halogenated organic herbicide type pesticides, and subsequent runoff of the agrochemicals and their degradation products from agricultural fields into sub-surface geological matter, are driving the on-going need for studying about the distribution (pervasiveness), transport (mobility), fate (i.e., as relating to persistence, degradation, transformation, or/and conversion), ecological risk, and health effects, of agrochemicals, particularly halogenated (especially, chlorinated) organic compound agrochemicals, in sub-surface geological matter, particularly, in the above stated water or aqueous forms of sub-surface geological matter, which are, or/and come in direct contact with, or/and lead to, sources of drinking water.
The persistence of halogenated organic herbicide type pesticides, in general, and CONHs, in particular, and their degradation products, in sub-surface geological matter has been widely reported [e.g., 2, 7-12]. Studies [7, 8, 13-15] by the U.S. Geological Survey (USGS) have shown that some parent CONHs, particularly atrazine, persist from year to year in sub-surface geological matter, such as soils and rivers, and that several CONH degradates are likewise persistent and mobile. Atrazine has a half-life of about 125 days, and because atrazine is not readily absorbed or adsorbed by soil particles, it is relatively mobile among sandy soils, further enabling atrazine to contaminate or pollute sub-surface geological matter. For example, in the US, atrazine has been found in the ground water of all 36 river basins studied by the USGS, and the USGS estimates that persistence of atrazine in deep lakes may exceed 10 years. Similar findings were obtained for diethylatrazine, an atrazine degradation byproduct, and it was reported [2] that concentrations of the parent compounds atrazine, alachlor and cyanazine, were occasionally observed above their MCLs in the Minnesota River. Well water surveys [e.g., 9] have shown that many sub-surface aquifers are contaminated with high levels of CONHs.
Numerous studies [e.g., 9, 10, 12-15] clearly indicate the on-going concern regarding possible health effects due to the presence of CONHs and their degradation products in sub-surface geological matter, particularly, in the above stated water or aqueous forms of sub-surface geological matter, which are, or/and come in direct contact with, or/and lead to, sources of drinking water. Many CONHs show acute and chronic toxicities at low concentrations [16-18], and they generally are known, or are suspected, to be carcinogenic, mutagenic, or/and teratogenic [2, 16-20].
In various countries, such as the US and EU (European Union) countries, throughout the world, use of some agrochemicals, such as atrazine, has been either greatly restricted or entirely banned [21], and levels of such agrochemicals in drinking water have been governmentally regulated. Despite such restrictions, bans, or/and regulations, many agrochemicals, and their degradation products, remain as major proven or potentially hazardous (poisonous or toxic), water contaminants or pollutants. Moreover, because conventional water treatment practices ordinarily do not remove soluble agrochemicals from the raw source waters being treated, agrochemical concentrations in drinking water can be equivalent to those in the raw source waters [8, 22-24].
In spite of proven and potential environmental and health hazards, many agrochemicals currently remain in widespread international use, thereby perpetuating the above described on-going problems caused by sub-surface geological matter contamination or pollution resulting from exposing agricultural substrates to agrochemicals.
Techniques for Treating or Remediating Sub-Surface Geological Matter Contaminated with Agrochemicals:
Although not a technique per se for treating or remediating the above stated types and forms of sub-surface geological matter which are contaminated or polluted with agrochemicals, the concept or principle of ‘natural attenuation’ is currently practiced for attempting to achieve or accomplish such treatment or remediation. ‘Natural attenuation’ (NA) generally refers to the natural occurrence or taking place of any number of various different physical, chemical, or/and biological types of natural phenomena, mechanisms, and processes, for example, involving degradation, transformation, conversion, sorption (i.e., adsorption-desorption), among others, which under favorable conditions cause or lead to ‘natural’ reduction or attenuation of various quantifiable parameters or properties, such as mass, toxicity, mobility, volume, or/and concentration, of organic contaminants or pollutants in geological matter, in general, and in sub-surface geological matter, in particular.
Aside from the continued practice of ‘natural attenuation’, there are numerous different types of techniques (methods, materials, compositions, devices, and systems) for treating or remediating the above stated types and forms of geological matter, in general, which may include sub-surface geological matter, which are contaminated or polluted with various different types and kinds of organic compound contaminants or pollutants, including those which may either be, or include, agrochemicals.
Each particular technique is primarily based on principles, phenomena, mechanisms, and processes, in one of the following main categories: (a) physical/physical chemical, (b) biological, or (c) chemical. A common ultimate objective of each geological matter treatment or remediation technique is to in-situ or/and ex-situ eliminate, or at least decrease, concentrations of the hazardous or potentially hazardous (poisonous or toxic) organic compound contaminants or pollutants, and desirably, also their degradation products, in the contaminated or polluted geological matter.
Physical/physical chemical techniques for treating or remediating geological matter contaminated or polluted with organic compounds, such as agrochemicals, are based on exploiting physical or physicochemical types of phenomena, mechanisms, and processes, such as filtration, for absorbing, adsorbing, and removing, the organic compounds; chemical destruction, whereby extreme conditions of temperature or/and pressure are used for breaking chemical bonds of the organic compounds; or/and photolysis, whereby UV (ultra-violet) light is used for breaking chemical bonds of the organic compounds. The organic compounds are ‘physically’ or ‘physicochemically’ removed or transported from the contaminated geological matter to another medium, such as a filter, or are degraded, transformed, or/and converted, in the contaminated geological matter to non-hazardous or/and less hazardous (poisonous or toxic) compounds.
Biological techniques for treating or remediating geological matter contaminated or polluted with organic compounds, such as agrochemicals, are based on exploiting biological (microbiological) types of phenomena, mechanisms, and processes, involving the use of biological organisms (such as microbes, microorganisms, bacteria), for ‘biologically’ degrading, transforming, or/and converting, the organic compounds in the contaminated geological matter to non-hazardous or/and less hazardous (poisonous or toxic) compounds.
Chemical techniques for treating or remediating geological matter contaminated or polluted with organic compounds, such as agrochemicals, particularly, the above described halogenated (especially, chlorinated) organic compounds, are based on exploiting non-catalytic chemical reaction, or (homogeneous or heterogeneous) catalytic chemical reaction, types of phenomena, mechanisms, and processes, involving the use of (inorganic or/and organic) chemical reagents, for ‘chemically’ degrading, transforming, or/and converting, for example, via reductive dehalogenating, the halogenated organic compounds in the contaminated geological matter to non-hazardous or/and less hazardous (poisonous or toxic) compounds.
A first specific example of such a chemical technique is that disclosed in PCT Int'l. Pat. Appl. Pub. No. WO 2006/072944, published Jul. 13, 2006, by the present applicant. Therein is disclosed a new diatomite/ZVM (zero valent metal)/electron transfer mediator composite, a method for manufacturing thereof, a method using thereof, and a system including thereof, for (in-situ or ex-situ) heterogeneously catalytically treating contaminated water, wherein the contaminated water is a form of ground water, surface water, above surface water, vapor, or/and gas. The composite is composed of a powdered diatomite (kieselguhr) support or matrix (optionally, including vermiculite) on or/and into which are incorporated at least one (preferably, porphyrinogenic organometallic complex type of) electron transfer mediator functioning as a catalyst, and zero valent metal (ZVM) nanometer sized particles, for example, having a size in a range of between about 5 nm and about 600 nm, functioning as a bulk electron donor or reducing agent. The composite type of heterogeneous catalyst is used for heterogeneously catalyzing reductive dehalogenation (especially, dechlorination) reactions, that are applied for catalytically treating or remediating contaminated or polluted water which includes, for example, halogenated organic compounds, particularly, halogenated organic solvents, such as chlorinated organic solvents.
In the composite, exemplary zero valent metals (functioning as a bulk electron donor or reducing agent) are zero valent transition metals, such as zero valent iron, cobalt, nickel, copper, or/and zinc. Preferably, the electron transfer mediator (functioning as the main catalytically active component of the heterogeneous composite) is a porphyrinogenic organometallic complex, such as a metalloporphyrin, for example, a chlorophyll (magnesium (II) complex) or a heme (iron (II) complex), or/and, a metalloporphyrin-like complex, for example, the metallocorrin type of organometallic complex, vitamin B12 (cyanocobalamin) (corrin ligand (a porphyrin analog) complexed to a cobalt (III) ion). For implementation, the heterogeneous composite is dispersed throughout the contaminated water under reducing (typically, anaerobic or anoxic) conditions, during which heterogeneous catalytic reductive dehalogenation reactions degrade, transform, or/and convert, the halogenated organic compounds in the contaminated water to non-hazardous or/and less hazardous compounds.
A second specific example of such a chemical technique is that disclosed in concurrently filed PCT patent application, entitled: “Catalytically Treating Water Contaminated With Halogenated Organic Compounds”, also by the present applicant. Therein is disclosed a new method of catalytically treating water contaminated with halogenated organic compounds, and a system thereof, wherein the halogenated organic compounds are chlorotriazine herbicides, chloroacetanilide herbicides, halogenated aliphatic herbicides, halogen containing analogs thereof, halogen containing derivatives thereof, or combinations thereof. The disclosed invention is applicable for (in-situ or/and ex-situ) homogeneously or/and heterogeneously catalytically treating such contaminated water being a variety of different forms, such as ground water (e.g., sub-surface water regions, reservoirs, or aquifers), surface water (e.g., rivers, lakes, ponds, pools, or surface water reservoirs), above surface water (e.g., above surface water reservoirs, or above surface sources or supplies of residential or commercial drinking water), or a combination thereof.
The disclosed method includes the main procedure of exposing the contaminated water to a catalytically effective amount of at least one electron transfer mediator under reducing conditions, to thereby decrease the concentration of at least one of the halogenated organic compounds in the contaminated water. The disclosed system includes: at least one electron transfer mediator; and at least one (in-situ or/and ex-situ) unit for containing a catalytically effective amount of the at least one electron transfer mediator, for exposing the contaminated water to the at least one electron transfer mediator under reducing conditions.
The disclosed invention is based on using a chemical technique for catalytically treating the contaminated water, by exploiting catalytic chemical reaction types of phenomena, mechanisms, and processes, involving the use of at least one electron transfer mediator functioning as an active redox catalyst under reducing (typically, anaerobic or anoxic) conditions, for in-situ or/and ex-situ, homogeneously or/and heterogeneously, catalytically degrading, transforming, or converting, in particular, via reductive dehalogenation (typically, dechlorination) of, the halogenated organic compounds in the contaminated water to non-hazardous or/and less hazardous (poisonous or toxic) chemical species. Implementation of the disclosed invention results in decreasing the concentration of at least one of the halogenated organic compounds in the contaminated water.
As disclosed therein, preferably, the at least one electron transfer mediator is a porphyrinogenic organometallic complex, an analog thereof, a derivative thereof, or any combination thereof. Preferably, the at least one porphyrinogenic organometallic complex is a metalloporphyrin complex, a metallocorrin complex, a metallochlorin complex, or any combination thereof. Preferably, the metalloporphyrin complex is composed of a transition metal complexed to a (initially free base) porphyrin selected from the group consisting of: tetramethylpyridilporphyrin, also named and known as [5,10,15,20-tetrakis(1-methyl-4-pyridinio)-porphine], herein, abbreviated and also referred to as [TMPyP]; tetrahydroxyphenylporphyrine, also named and known as [5,10,15,20-tetrakis(4-hydroxyphenyl)-21H, 23H-porphine], herein, abbreviated and also referred to as [TP(OH)P]; tetraphenylporphyrin, also named and known as [5,10,15,20-tetraphenyl-21H,23H-porphine], herein, abbreviated and also referred to as [TPP]; and 4,4′,4″,4′″-(porphine-5,10,15,20-tetrayl)tetrakis(benzenesulfonic acid), herein, abbreviated and also referred to as [TBSP].
The transition metal is essentially any transition metal capable of complexing with the just stated porphyrins for forming the corresponding metalloporphyrin complex. Preferably, the transition metal is cobalt [Co], nickel [Ni], iron [Fe], zinc [Zn], or copper [Cu]. Additional exemplary metalloporphyrin complexes which are suitable for implementing the disclosed invention are chlorophylls [magnesium (II) complexes], and hemes [iron (II) complexes]. An exemplary metallocorrin complex is vitamin B12 [corrin ligand (porphyrin analog) complexed to a cobalt (III) ion].
Catalytically treating the contaminated water, involving catalytic degradation, transformation, or conversion, of the halogenated organic compounds in the contaminated water to non-hazardous or/and less hazardous chemical species, thereby decreasing the concentration of at least one of the halogenated organic compounds in the contaminated water, is effected according to homogeneous catalysis or/and according to heterogeneous catalysis, under reducing (anaerobic or anoxic) conditions. According to homogeneous catalysis, the catalytically effective amount of the at least one electron transfer mediator (catalyst) is an initially solid (typically, particulate) particulate substance that is non-supported, non-matrixed, non-intercalated, or/and non-trapped, by another material, and subsequently becomes freely mobile and soluble throughout the contaminated water. According to heterogeneous catalysis, the catalytically effective amount of the at least one electron transfer mediator (catalyst) is an initially solid (typically, particulate) substance that is supported, matrixed, intercalated, incorporated, or/and trapped, and generally immobile, on or/and inside of a (particulate or/and non-particulate) solid support or matrix material which subsequently becomes dispersed (i.e., not dissolved) throughout the contaminated water. Ordinarily, the initially immobilized catalytically effective amount of the at least one electron transfer mediator (catalyst) similarly becomes dispersed (i.e., not dissolved) throughout the contaminated water. However, any one or more immobilized electron transfer mediator may at least partially dissolve in the contaminated water, depending upon actual parameters and conditions of a given heterogeneous catalytic chemical reaction system during implementation of the disclosed invention.
For implementing the disclosed invention according to heterogeneous catalysis, in general, essentially any type of heterogeneous catalyst (preferably, but not limited to being, particulate) solid support or matrix material can be used for supporting, matrixing, and immobilizing, the at least one electron transfer mediator (catalyst). Exemplary types of suitable (particulate or/and non-particulate) solid support or matrix materials are diatomite (kieselguhr), amorphous silicas, crystalline silicas, silica gels, aluminas, minerals, ceramics, carbohydrates (such as sepharose, sephadex), clays, plastics (such as polystyrene), composites, and combinations thereof. A specific example of such an electron transfer mediator solid supported or matrixed configuration is the hereinabove previously described present applicant's diatomite/ZVM (zero valent metal)/electron transfer mediator composite type of heterogeneous catalyst.
Exposing the contaminated water to the catalytically effective amount of the at least one electron transfer mediator is performed, for example, according to homogeneous catalysis or according to heterogeneous catalysis, each via a batch mode, or, alternatively, each via a flow mode, for forming a respective homogeneous or heterogeneous catalytic reaction system of either mode, under reducing (anaerobic or anoxic) conditions, i.e., when reducing conditions, as opposed to oxidizing conditions, are prevalent in the contaminated water. According to homogeneous catalysis, via a batch or flow mode, either part of, or the entire, catalytically effective amount of the at least one electron transfer mediator is used ‘as is’, in a particulate form, i.e., as a generally dry, single particulate substance or mixture of several particulate substances. Alternatively, or additionally, prior to exposure to the contaminated water, either part of, or the entire, catalytically effective amount of the at least one electron transfer mediator is dissolved in one or more suitable (aqueous or/and organic) solvents at suitable conditions (temperature, pH, mixing), and then used in a solution form, i.e., as a solution of a dissolved single particulate substance or as a solution of a dissolved mixture of several particulate substances. According to heterogeneous catalysis, via a batch or flow mode, ordinarily, the entire catalytically effective amount of the at least one electron transfer mediator is used ‘as is’, in a particulate form, i.e., as a generally dry, single particulate substance or mixture of several particulate substances, of one or more electron transfer mediator solid supported or matrixed configurations.
Reducing conditions naturally exist, or/and are anthropogenically (human) produced, in the contaminated water. When reducing conditions are not present in the contaminated water, or are considered insufficient for effectively enabling the phenomena, mechanisms, and processes, of the electron transfer mediated (homogeneous or heterogeneous) catalytic reductive dehalogenation reactions, for catalyzing reductive dehalogenation of the halogenated organic compound contaminants in the contaminated water, then, there is need for anthropogenically producing the reducing conditions in the contaminated water.
Anthropogenically producing the reducing conditions in the contaminated water is performed by exposing the contaminated water to at least one bulk electron donor or reducing agent, immediately before, or/and during, or/and immediately after, exposing the contaminated water to the catalytically effective amount of the at least one electron transfer mediator. Alternatively, anthropogenically producing the reducing conditions in the contaminated water is performed by using an electron transfer mediator solid supported or matrixed configuration type of heterogeneous catalyst that already includes at least one bulk electron donor or reducing agent as part of the heterogeneous catalyst structure or composition.
In general, essentially any bulk electron donor or reducing agent capable of reducing an electron transfer mediator under reducing (anaerobic or anoxic) conditions can be used for implementing the disclosed invention. Preferably, the at least one bulk electron donor or reducing agent includes an elemental metal (zero valent metal), such as iron [Fe], lithium [Li], sodium [Na], potassium [K], beryllium [Be], magnesium [Mg], titanium [Ti], or any mixture thereof. Alternatively, the bulk electron donor or reducing agent compounds is titanium citrate [Ti(OC(CH2COOH)2COOH], potassium borohydride [KBH4], sodium borohydride [NaBH4], lithium hydride [LiH], potassium hydride [KaH], sodium hydride [NaH], borotrihydride [BH3], aluminum trihydride [AlH3], hydrazine [H2NNH2], triphenylphosphate [PPh3], sodium dithionite (sodium hydrosulfite) [Na2S2O4], or any combination thereof.
In general, for implementing the disclosed invention, the extent of time or duration (for example, hours, days, weeks, etc.) of exposing the contaminated water to the catalytically effective amount of the at least one electron transfer mediator, under reducing conditions, depends upon a variety of parameters and conditions of a given batch or flow mode homogeneous or heterogeneous catalytic reaction system. Exemplary applicable in-situ units for containing the catalytically effective amount of the at least one electron transfer mediator as a heterogeneous catalyst are either in a form as at least part of a ground water permeable reactive barrier (PRB) configured as a continuous filled in trench or wall, or as a stand-alone filled in well, or, in a form as part of a groundwater pumping and treatment system. An exemplary applicable ex-situ unit for containing the catalytically effective amount of the at least one electron transfer mediator as a homogeneous catalyst or/and as a heterogeneous catalyst is in a form as part of an above surface water treatment reactor system. The disclosed invention is generally applicable for catalytically treating water contaminated with other types or kinds of halogenated organic compounds, not limited to being halogenated organic herbicides, halogen containing analogs thereof, or halogen containing derivatives thereof.
The above summarized techniques are generally applicable for treating or remediating any of the above stated types and forms of geological matter, which may include sub-surface geological matter, which are contaminated or polluted with various different types and kinds of organic compound contaminants or pollutants, including those which may either be, or include, agrochemicals. However, the field and scope of the present invention are particularly directed to decreasing or preventing, specifically, ‘sub-surface’ geological matter (e.g., ground or earth, or/and water) contamination by agrochemicals.
Origin and Main Processes of Sub-Surface Geological Matter Contamination Resulting from Exposing Agricultural Substrates to Agrochemicals:
Any given technique for treating or remediating geological matter, in general, and sub-surface geological matter, in particular, contaminated or polluted with organic compound contaminants or pollutants, including those which may either be, or include, agrochemicals, typically has any number and types of advantages and disadvantages, depending upon the actual properties, parameters, characteristics, types and forms, and behavior, of the agricultural substrate(s), the agrochemical(s), and the sub-surface geological matter. Before describing specific problems and limitations of techniques for treating or remediating sub-surface geological matter contaminated with agrochemicals, it is useful to first briefly describe the origin and main processes of sub-surface geological matter contamination resulting from exposing agricultural substrates to agrochemicals.
Following applying or dispensing to, or/and upon, outer surfaces or/and immediately surrounding environments of plant matter or/and animal matter types of agricultural substrates, as part of cultivating, breeding, raising, developing, growing, or maintaining, the agricultural substrates, then, eventually, any number and types of naturally occurring moisture (i.e., in the air or atmosphere), dew, rain, snow, sleet, irrigation, or/and, human or/and machine washing of, or applying water to, the agricultural substrates (and agrochemicals upon them), as well as the immediately surrounding environment hosting or surrounding the agricultural substrates, wet the agricultural substrates, and typically, also the immediately surrounding environment hosting or surrounding the agricultural substrates. Thereafter, the water soluble and mobile agrochemicals, and possible initial degradation products thereof, become dissolved, transported, and, as a result of various diffusion, adsorption, desorption, and mass transfer processes, become heterogeneously distributed into, throughout, and among, various different horizontally or/and vertically extending zones or regions of the above stated types and forms of sub-surface geological matter.
Such zones or regions of the different forms of sub-surface geological matter begin at, and extend to, varying depths below or beneath the top or uppermost surface layer of a form of ground or earth, or of a form of water. For example, such zones or regions of sub-surface geological matter typically begin from a depth of about 5 centimeters, and can extend to a depth of about 2000 meters, below or beneath the top or uppermost surface layer of a form of ground or earth, or of a form of water. In the particular case where the sub-surface geological matter is an underground water reservoir, well or spring, or ground water, then, dissolution, transport, and heterogeneous distribution, of the agrochemical contaminants or pollutants may generate relatively large horizontally or/and vertically extending contaminant zones or regions, which are well known in the field and art as contaminant plumes (i.e., specific ground water zones or regions concentrated with contaminants or pollutants).
Main Problems and Limitations of Techniques for Treating or Remediating Sub-Surface Geological Matter Contaminated with Agrochemicals:
A main problem and limitation of practicing natural attenuation (NA) is based on the fact that it essentially entirely depends upon ‘naturally’ reducing or attenuating the various quantifiable parameters or properties, such as mass, toxicity, mobility, volume, or/and concentration, of the agrochemical contaminants or pollutants in the sub-surface geological matter. Meaningful natural attenuation can require time periods of on the order of years, thus accounting for the relatively long persistence of agrochemical contaminants or pollutants in sub-surface geological matter.
In the particular case where the contaminated or polluted sub-surface geological matter is an underground water reservoir, well or spring, or ground water, then, by practicing natural attenuation, long time periods of continuous underground water flow are often required for the various quantifiable parameters or properties of the agrochemical contaminants or pollutants, and possible degradation products, to be sufficiently decreased or attenuated in the underground water. In contrast to river water, which has a turnover time on the order of two weeks, ground water residence times are on the order of about 2 weeks to about 10,000 years. Additionally, the large horizontally or/and vertically extending, and heterogeneous, contaminant zones or regions (contaminant plumes) of underground water types of contaminated sub-surface geological matter tend to be very difficult to locate, detect, characterize, and treat or remediate.
Point (Localized) and Non-Point (Diffused) Sources of Contamination or Pollution:
In the field and art of environmental science and technology focusing on decreasing or preventing contamination of geological matter, in general, and of sub-surface geological matter, in particular, a given source of contamination or pollution can be categorized as either being a ‘point (localized)’ source of contamination or pollution, or as being a ‘non-point (diffused)’ source of contamination or pollution.
A ‘point (localized)’ source of contamination or pollution generally refers to any discernible, confined, or/and discrete, means of material conveyance or transport, including, but not limited to, pipes, ditches, channels, tunnels, conduits, wells, discrete fissures, containers, rolling stocks, concentrated animal feeding operations, or, vessels or other floating crafts, from which contaminants or pollutants, such as organic compound contaminants or pollutants, including those which may either be, or include, agrochemicals, are, or may be, discharged. A ‘non-point’ source of contamination or pollution generally refers to a source or potential source of contaminants or pollutants having a relatively large areal dimension that is not constrained to a single point or location of origin, or to a single stack, or is not introduced into a receiving stream from a specific outlet or source. Diffuse or non-point contaminant or pollution sources can be divided into source activities related to either land or water use, including failing septic tanks, improper animal-keeping practices, forest practices, and, urban and rural water runoff, and of course, sub-surface geological matter contamination resulting from exposing agricultural substrates to agrochemicals.
Another significant problem and limitation of techniques for treating or remediating sub-surface geological matter contaminated or polluted with agrochemicals, is based on the inherently fundamental and practical differences of the above two main categories of ‘point (localized)’ and ‘non-point (diffused)’ sources of contamination or pollution. Most, but not all, techniques for treating or remediating sub-surface geological matter contaminated or polluted with agrochemicals are practiced on point (localized), and not on non-point (diffused), sources of contamination or pollution. Attempting to practice treating or remediating techniques on non-point (diffused) sources of contamination or pollution, especially on large scale commercial agricultural or agricultural types of processes, inherently introduces a variety of problems and limitations, not the least of which are based on the relatively large amounts of human and financial resources needed to implement such practice. However, many large scale commercial agricultural or agricultural types of processes, such as those which involve applying or dispensing to, or/and upon, outer surfaces or/and immediately surrounding environments of plant matter or/and animal matter types of agricultural substrates, as part of cultivating, breeding, raising, developing, growing, or maintaining, the agricultural substrates, that cause sub-surface geological matter contamination, are characterizable as being in the category of non-point (diffused) sources of contamination or pollution. Thus, most techniques are inherently limited for treating or remediating sub-surface geological matter contaminated or polluted with agrochemicals, involving large scale commercial agricultural or agricultural types of processes.
Another, possibly even more significant problem and limitation of techniques for treating or remediating sub-surface geological matter contaminated or polluted with agrochemicals, is based the fact that most are practiced or implemented ‘at the depth’ of the immediate zone or region of the contaminants or pollutants. Such is the case when implementing treatment or remediation techniques based on use of in-situ permeable reactive barriers (PRBs), which involve placing or locating the treating or remediating ‘active’ substance(s) or material(s) in trenches or walls, or in stand-alone filled in wells, at the various depths of, typically, several separately located contaminant plumes. A similar case arises when implementing ‘pump-and-treat’ types of treatment or remediation techniques based on use of ground water pumping and treatment methods, equipment, and systems. This technique requires pumping the contaminated or polluted water from ‘at the depth’ of the immediate zone or region of the contaminants or pollutants, to an above surface, typically, off-site, location for treatment or remediation. Here too, relatively large amounts of human and financial resources are needed to successfully implement such techniques.
Based on the above described problems and limitations of techniques for treating or remediating geological matter, in general, and sub-surface geological matter, in particular, contaminated or polluted with organic compound contaminants or pollutants, including those which may either be, or include, agrochemicals, are ordinarily not technologically or/and economically feasible or viable for decreasing or preventing sub-surface geological matter contamination resulting from exposing agricultural substrates to agrochemicals. This is especially the case when large scale commercial agricultural or agricultural types of processes are involved.
Despite the numerous different types of techniques (methods, materials, compositions, devices, and systems) for treating or remediating geological matter, in general, which may include sub-surface geological matter, contaminated or polluted with various different types and kinds of organic compound contaminants or pollutants, including those which may either be, or include, agrochemicals, and in view of the above described problems and limitations of such techniques, there is a real and significant need for an entirely new approach to ‘attack and solve’ the problem of sub-surface geological matter contamination. In particular, there is a need for attacking and solving the problem of sub-surface contamination, upstream, and, ‘spatially and temporally’ closer, to the source(s) or point(s) of generation of the agrochemical contaminants or pollutants.
There is thus a need for, and it would be highly advantageous to have a method of exposing an agricultural substrate (plant matter, animal matter) to an agrochemical, and a method of decreasing or preventing sub-surface geological matter contamination resulting from exposing an agricultural substrate to an agrochemical. There is also a need for having such an invention which includes a composition used in those methods, and to an article-of-manufacture including the composition.
Moreover, there is a need for such an invention which is generally applicable to a wide variety of different plant matter or/and animal matter types and kinds of agricultural substrates. There is a further need for such an invention which is generally applicable to a wide variety of different categories, sub-categories, groups, sub-groups, and classes, of agrochemicals. There is a further need for such an invention which is generally applicable to a wide variety of different forms of ground or earth, or/and water, types of sub-surface geological matter. There is a further need for such an invention which is generally applicable to decreasing or preventing a wide variety of different types and kinds of ‘point (localized)’ and ‘non-point (diffused)’ sources of sub-surface geological matter contamination.
Moreover, there is a need for such an invention which is technologically and economically feasible, and highly effective for attacking and solving the problem of sub-surface geological matter contamination upstream, and, spatially and temporally closer, to the source(s) or point(s) of generation of the agrochemical contaminants or pollutants, that would allow continued use of agrochemicals in agricultural or/and agricultural types of processes without adversely affecting the environment.